Screw-propeller.



A. J. MAcDONALD.

SCREW PROPELLEH.

APPLICATION FILED SEPT. 10. 1913.

Patented Sept. 26,1916.

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SCREW-PROPEPLER.

Specification of Letters Patent.

Patented Sept. 26, 191.6.

Applicgtion filegl September 10, 1913. Serial No. 783,214.

To all whom it may concern:

Be it known that :I, ANcUs J. MAoo vALD, of the town of Amherst, in the county of Cumberland, Province of Nova Scot1a,

Dominion of Canada, have invented certain new and useful Improvements in Screw- Propellers, of which the following is a specification.

This invention relates to improvements in screw propellers, and the objects of the invention are to devise an improved propeller that is of great efliciency, comparatively inexpensive of manufacture, and further, that will not get clogged by having natural water-weeds bind themselves around its hub. An additional advantage of this propeller is the additional strength consequent on the formation of the blades from one piece of metal.

The invention consists essentially inthe novel and improved construction and arrangement of parts hereinafter described, and illustrated in the accompanying drawing which forms part of this specification.

In the drawing :Figure 1 is a view in perspective of the arrangement of blade and hub, according to my invention. Fig. 2 is an elevation, partly in section, of the blade, hub, and hub sheath or guard. Fig. 3 is a side elevation of the hub and blade. Fig. 4 shows one method of forming or cutting the blade, illustrating the shape when flat. Fig. 5 shows an elevation arrangement of another form of the blade constructed according to my invention. Fig. 6 shows another method of cutting the blade, or its form when developed, alternate to that illustrated in Fig. 4:. Fig. 7 shows in perspective a view of the sheath used to guard the propeller hub from weeds andthe like.

In the drawings like numerals of reference indicate corresponding parts in all the figures.

Referring to the drawings, and especially to Figs. 1, 2 and 3, the formation of the blade of the propeller will be seen to consist of oppositely disposed and curved, wings or arms, 2 and 3, which are formed in one piece with the main body 1 of the propeller.

elis a sleeve-like hub, secured or formed integral with, the main body, and in line with its axis, being suitably bored to receive the tail-shaft of a boat.

The blade may be made of a piece of sheetsteel as illustrated in Fig. 4, being more or less in the shape of a segment of a circle, terminating at the edges 5 and 6, and having the axis 7 The blade may also be fashioned from a smaller segment as shown in Figs. 5 and 6, and in other respects be bent after the fashion of the blade disclosed in Figs. 1, 2 and 3, only having the edges 5 and 6 necessarily set at'a more acute angle to the axis 7 than would be the case when made as shown in Figs. 1, 2 and 3.

If the blade be made of sheet metal, the hub 4 may be welded to the blade, or secured in any suitable fashion. Otherwise the pro peller may be cast as a whole, or forged, if such be more convenient.

The means of securing the propeller to the shaft that I prefer to use, consist of counter-sunk or the like set-screws whose heads 9 are flush with the outside of the hub, and which are provided with square recesses 10' adapted to receive a key for tightening purposes.

An important feature of my invention is the protecting sheath 12, (Fig. 7) which is illustrated in its operative position in Fig. This is formed as a tubular casing for the hub of the propeller, which it protects from anything in the water that might bind on the revolving hub, and get wrapped around it, and is provided with a flange or lugs 13 having holes 1% suitable for receiving bolts or other securing means for rigidly fastening the sheath to the ships hull.

As many changes could be made in the above construction, and many apparently different embodiments of my invention constructed within the scope of the claims without departing from the spirit or scope thereof, it is intended that all matter contained in the accompanying specification and drawings shall be interpreted as illustrative and not in a limiting sense.

lVhat I claim as my invention is:

1. A screw propeller comprising a single piece of metal forming the major sector of a circle having its free ends bent curvilinearly on opposite sides and its radial edges disposed at substantial right angles to the longitudinal axis and an integral hub extending from the center and rigid with the said piece.

2. In a screw propeller, a single piece of metal forming a pair of blades of opposite arc section having their line of contrary flexure in alinement with the axial line of the propeller and emanating as portions of sunk in their normal position, said heads 1 cone shells from a common point forming having a squared recess. the apex of said cone sections and having In Witness whereof I have hereunto set their rafdizil epljigecsl' angullarly disposed tlo the my hand in the presence of tWo Witnesses.

ocv o t e a es 11K cesi ned to ie in the same plane; a hub porti%n rigid with ANGUS JOSEPH MACDONALD said blades adjacent to said common point Vitnesses: on said axial line, and transverse set-screws A. V. FIDLEs, threaded into said hub having their heads R. FRASER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. G. 

